Wavelength selectable, controlled chirp, semiconductor laser
OwnerAram Mooradianinventor
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Abstract
A wavelength selectable, controlled chirp, semiconductor laser system is provided. By coupling a passive cavity, including an external output mirror with a selected reflectivity, to the active cavity of a laser device, chirp is reduced by approximately the ratio of the length of the active cavity to the length of the passive cavity. In such a device, changing the length of the passive cavity by manipulating the position of the output mirror allows for selecting an output wavelength of the laser device.
Claims25
A reduced-chirp semiconductor laser device comprising:
- an active cavity including an active gain region disposed between a first mirror and a second mirror, and characterized by an active cavity chirp value;
- and
- a passive cavity including a substantially optically transparent passive cavity material disposed between the second mirror and a third mirror, wherein
- the third mirror reflectivity and the passive cavity length are adapted to reduce a chirp of the laser device by substantially at least a factor of two over the active cavity chirp value.
A method for reducing chirp in a semiconductor laser device having an active cavity including an active gain region disposed between first and second mirrors, comprising the steps of:
- providing a third mirror with a third mirror reflectivity;
- positioning the third mirror a selected distance from the active cavity, wherein the third mirror reflectivity and the distance of the third mirror from the active cavity are selected to reduce a chirp of the laser device below a selected value.
A method for setting a wavelength of a light beam output from a controlled chirp semiconductor laser including an active cavity and a passive cavity including an output mirror, comprising the steps of:
- selecting a desired light beam wavelength;
- operating the laser to output a light beam;
- detecting a wavelength of the output light beam;
- selecting a location for the output mirror by manipulating a position of the output mirror to adjust the ratio of the passive cavity length to the active cavity length to adjust the wavelength of the output laser beam until the output laser wavelength is substantially equivalent to the selected output wavelength;
- fixing the output mirror at the selected location.
A method for making a wavelength selectable, controlled chirp semiconductor laser comprising the steps of:
- creating on a substrate an active cavity including a gain region disposed between a substantially fully reflective mirror and a partially reflective mirror;
- creating a passive cavity, including an external output mirror, coupled to the active cavity to control a chirp of the active cavity;
- selecting a desired output light beam wavelength;
- operating the laser to output a light beam;
- detecting the wavelength of the output light beam;
- selecting a position of the output mirror by manipulating the position of the output mirror to adjust the ratio of the passive cavity length to the active cavity length to adjust the wavelength of the output laser beam until the laser outputs the selected output wavelength;
- fixing the output mirror at the selected position.
Dependencies are inferred from the claim text.